How to Wash Tencel and Lyocell
Tencel (lyocell) fibrillates — wet mechanical agitation peels micro-fibrils from the fibre surface, creating fuzz or pilling. This is unique to lyocell; cotton and linen do not fibrillate. Enzyme (biological) detergent also attacks lyocell cellulose. Cold 30°C gentle cycle, enzyme-free detergent, low spin, air dry flat.
The Chemistry
Tencel is a brand name for lyocell fibre, produced by Lenzing AG. Lyocell is a regenerated cellulose fibre made from wood pulp (most commonly eucalyptus, though beech and other sustainably managed trees are also used). The "regenerated" part is important: the cellulose polymer is dissolved and re-spun, unlike cotton or linen where the fibre is used in its native plant form. The production process is what makes lyocell environmentally distinctive compared to other regenerated celluloses like viscose (rayon). Traditional viscose production dissolves cellulose using sodium hydroxide and carbon disulphide (NaOH + CS₂). Carbon disulphide is toxic and the process generates significant chemical waste. Lyocell production uses N-methylmorpholine N-oxide (NMMO) — a non-toxic solvent that dissolves cellulose directly without chemical derivatisation. Crucially, the NMMO is recovered and recycled in a closed loop at recovery rates exceeding 99%. This is the environmental claim behind Tencel's sustainability marketing, and it is accurate. The dissolution and re-precipitation process produces a fibre with cellulose II crystal structure. Native plant cellulose (cotton, linen) exists as cellulose I, where the polymer chains are arranged in parallel. When cellulose is dissolved and re-precipitated from solution, it crystallises into cellulose II, where adjacent chains are arranged antiparallel. Cellulose II is thermodynamically more stable (lower free energy) than cellulose I — this is why cotton cannot be converted back from cellulose II to cellulose I. The different chain arrangement means the hydrogen bonding network is different, and the resulting fibre has different mechanical properties: lyocell has high dry tensile strength (comparable to polyester) but, crucially, lower wet strength than cotton. The most important care implication of lyocell's structure is fibrillation. Fibrillation is a phenomenon unique to lyocell among common textile fibres. The lyocell fibre has a highly oriented, crystalline structure with fibril bundles running longitudinally along the fibre axis. When a wet lyocell fibre is subjected to mechanical stress — rubbing against itself, against other fibres in a wash drum, or against a wash drum wall — the surface micro-fibrils are abraded and peel away from the main fibre body. They remain attached at one end and project outward from the fibre surface. This fibrillation can manifest in two ways depending on degree: mild fibrillation creates a soft, matte, peach-skin or suede-like texture that is actually a desirable finishing effect used in some high-end garments (deliberate enzymatic bio-polishing then fibrillation is used to create specific fabric aesthetics). More extensive or uncontrolled fibrillation creates visible surface fuzz, pilling, and a loss of the smooth, drapey character that makes lyocell distinctive. Once uncontrolled fibrillation occurs, it cannot be reversed by home methods. Commercial Tencel garments are typically bio-polished before sale — treated with cellulase enzymes at the finishing stage. These enzymes break down the surface micro-fibrils and leave a smooth, polished surface that is more resistant to further fibrillation. However, this bio-polish is not permanent. Washing at high temperatures, with enzyme detergent, or with excessive mechanical agitation removes the bio-polish protection over time. Cellulase enzyme in laundry detergent (the same enzyme used in bio-polishing, but applied uncontrollably in the wash) can attack both the surface micro-fibrils and, at higher temperatures, the main fibre cellulose chain. This is particularly damaging to lyocell because the micro-fibril structure makes more surface area available for cellulase attack than a flat cotton surface. The correct care for Tencel/lyocell is cold water (30°C or below), a gentle/delicates cycle with low drum rotation speed, reduced spin speed (low spin prevents mechanical stress on wet fibre), and air drying flat or hanging without wringing. Enzyme-free or synthetic fibre detergent is recommended if you want to preserve the bio-polish finish long-term. The garment label often says "gentle wash, do not tumble dry" for exactly these reasons. Lyocell is not the same as modal, although they are often confused. Modal is also a regenerated cellulose fibre, but made from beech wood using a modified viscose process (not the NMMO process). Modal has higher wet strength than standard viscose but does not fibrillate in the same way as lyocell. Tencel (lyocell) has higher dry strength than modal but the distinctive fibrillation sensitivity. A Tencel-modal blend has intermediate properties.
Step-by-step
- 1
Machine wash cold (30°C or below) on a gentle or delicates cycle — hot water and normal agitation cause fibrillation
Lyocell fibrillates when wet fibres are mechanically abraded — surface micro-fibrils peel away and create fuzzing or pilling. Cold water reduces fibre swelling slightly, and the gentle cycle's lower drum rotation speed reduces the mechanical stress on wet fibres. Use 30°C or below. Never wash at 40°C or above: higher temperatures both accelerate fibrillation and accelerate degradation of the bio-polish finish applied during manufacturing.
- 2
Use an enzyme-free detergent — cellulase enzyme in biological detergent attacks lyocell fibres
Cellulase enzyme in biological laundry detergent degrades cellulose. While this helps remove cotton-based soiling (dead skin cells, cotton fabric pills), it also attacks lyocell fibre surfaces. Tencel's micro-fibril structure provides more surface area for cellulase than flat cotton, making lyocell more vulnerable. Use a synthetic-fibre detergent or a formula specifically labelled enzyme-free. Persil Silk & Wool, Woolite, or similar delicates formulas are appropriate. Avoid all biological/enzyme-containing detergents for Tencel garments.
- 3
Reduce spin speed — high spin applies mechanical stress to wet lyocell and initiates fibrillation
High spin speed (1000 rpm and above) creates significant centrifugal force on wet fabric, pressing fibres against the drum wall and against each other. Wet lyocell is more susceptible to mechanical stress than dry lyocell. Set spin speed to 400–600 rpm maximum for Tencel garments. If your machine has a 'no spin' option, use it for particularly delicate lyocell pieces and remove the garment after the wash cycle before spin.
- 4
Do not tumble dry — heat and drum tumbling cause both fibrillation and shrinkage
The tumble dryer combines two threats for Tencel: mechanical agitation (drum rotation with the garment tumbling freely, creating fibre-against-fibre and fibre-against-drum abrasion) and heat (which accelerates fibre relaxation and shrinkage). Do not tumble dry lyocell. Air dry flat on a towel or drying rack, or hang from the hem. Reshape the garment while slightly damp — lyocell is slightly elastic when damp and can be gently stretched back to shape if it has relaxed.
- 5
Iron inside-out on a low-medium setting while damp — do not iron bone dry
Tencel/lyocell wrinkles fairly easily but responds well to ironing. Use a cool-to-medium iron setting (silk/synthetics, approximately 110–150°C) on the wrong side of the fabric. Do not use the high linen or cotton setting — the high-crystallinity cellulose II structure of lyocell is more susceptible to surface sheen and potential fibre damage at linen temperatures. The fabric should be slightly damp when ironed — the same damp ironing principle as linen applies, but at a lower temperature. Steam iron setting is acceptable.
- 6
Store flat or loosely folded — Tencel drapes well but the weight of heavy items causes creasing
Tencel has excellent drape due to its smooth fibre surface and the way the cellulose II crystalline structure gives the fibre flexibility. Hang lighter garments (blouses, dresses) on padded hangers. Fold heavier items. Avoid storing compressed under heavy items — creases set in lyocell, though they are more easily released than in linen because the amorphous fraction of cellulose II is higher. Store clean — body oils left in the fabric can cause yellowing over time.
Tencel washing guide by type
| Type | Wash | Spin | Drying | Iron | Notes |
|---|---|---|---|---|---|
| Pure Tencel/lyocell garment | Cold 30°C, gentle cycle, enzyme-free detergent | 400–600 rpm maximum | Air dry flat or hang — no tumble dryer | Damp, inside-out, medium setting (110–150°C) | Fibrillation risk from high agitation, hot water, enzyme detergent |
| Tencel-cotton blend | Cold/30°C, gentle cycle | Low spin | Air dry; low-heat tumble dry acceptable | Medium cotton setting on reverse | Cotton adds durability; lyocell still sets the upper limit |
| Tencel-modal blend | Cold 30°C, gentle cycle | Low spin | Air dry flat | Medium setting, damp | Modal doesn't fibrillate like lyocell; cold is still safer |
| Tencel-polyester blend | 30°C, gentle cycle | Medium spin acceptable | Low-heat tumble dry or air dry | Medium or lower — check polyester component | Polyester adds durability; microplastics: wash in Guppy bag |
| Tencel workwear / structured shirts | 30°C, gentle cycle | Low spin | Hang to dry; iron damp | Damp, inside-out, medium setting | Structured garments benefit from reshaping on hanger while damp |
| Modal (beech cellulose) — not lyocell | 30–40°C, gentle or normal cycle | Medium spin acceptable | Low-heat tumble dry acceptable | Medium-low setting | Modal does not fibrillate; slightly different care from Tencel |
Frequently asked questions
What is fibrillation and why does Tencel fibrillate?
Fibrillation is a process unique to lyocell (Tencel) among common textile fibres. Lyocell has a highly oriented, crystalline internal structure with micro-fibril bundles running along the length of each fibre. When a wet lyocell fibre is mechanically abraded — rubbing against other fibres in a washing machine drum, against the drum wall, or against clothing during wear — these surface micro-fibrils are peeled away from the main fibre body. They remain attached at one end and project outward. Mild fibrillation creates a soft peach-skin texture sometimes used intentionally. Uncontrolled fibrillation creates surface fuzz and pilling. It cannot be reversed at home once it occurs.
Can Tencel go in the washing machine?
Yes, but with specific settings. Cold water (30°C maximum), a gentle or delicates cycle, low spin speed (400–600 rpm), and enzyme-free detergent. Hot water accelerates fibrillation by increasing fibre swelling and micro-fibril mobility. Normal cycles have higher drum rotation speeds that create more mechanical stress on wet fibres. Enzyme detergent (biological detergent) contains cellulase, which attacks lyocell cellulose. All three of these — hot water, high agitation, enzyme detergent — damage Tencel. Use all three precautions together, not just one.
Is Tencel the same as modal or viscose?
No. Tencel is lyocell, produced using NMMO (N-methylmorpholine N-oxide) solvent in a closed-loop process. Modal is a regenerated cellulose fibre from beech wood produced via a modified viscose process — it has higher wet strength than standard viscose but does not use the NMMO process and does not fibrillate like lyocell. Viscose (rayon) is the oldest regenerated cellulose, produced using NaOH/CS₂, lowest wet strength of the three (loses 40–50% strength when wet), and most prone to shrinkage. The three behave differently in washing: viscose is the most fragile, lyocell has the fibrillation risk, modal is intermediate. Check your garment label carefully.
Why does Tencel say 'do not tumble dry' on the label?
Tumble drying is harmful to Tencel for two reasons. First, the mechanical action: the garment tumbles freely in the drum, creating continuous fibre-on-fibre and fibre-on-drum abrasion on wet fabric — exactly the conditions that cause fibrillation. Second, the heat: lyocell shrinks under heat as the fibre relaxes from its spun and woven tension. The combination of heat and agitation in a tumble dryer rapidly removes the bio-polish protection applied during manufacturing, causes fibrillation, and causes shrinkage. Air drying flat or hanging from the hem avoids all three problems.